2009 Kona CoilAir MagicLink

To say that we were surprised when the invitation to the Kona MagicLink launch arrived would be a bit of an understatement. You see, the pre-production bike that was unveiled last summer in Livigno seemed so far from completion that we thought it might never materialise. Well, it turns out we couldn’t have been more wrong.
And in something of a departure from recent years, there were even rideable samples. On hand to answer our questions was Brian Berthold, the designer of the MagicLink suspension system, with Kona even providing a photographer to service our needs.
Why such an about-turn? Well, Kona’s suspension bikes haven’t changed much over the years and the MagicLink has a lot going on, mechanically speaking, so you could say that Kona wanted to ensure that it had our undivided attention.

Reworked CoilAir

The first bikes in the Kona range to sport the new MagicLink suspension design are the three CoilAir models. The addition of the link and auxiliary shock has Kona claiming that the rear suspension now has 6 to 7.4in of travel.
But, this is somewhat confusing, as the only way the bike could ever have 6in of travel is if you were to replace the auxiliary shock with a solid blank. Compounding the confusion surrounding the new design are the diagrams showing how the geometry of the CoilAir changes when the MagicLink compresses the auxiliary shock. Seeing as this doesn’t happen in isolation and occurs on any full-suspension bike when the rear suspension alone is compressed or extended, it’s best to ignore it. If you just think of the new CoilAir as a 7.4in-travel bike you stand a better chance of understanding how it works.

5-Bar Linkage

By attaching the swingarm to the MagicLink, Kona’s suspension design has been transformed from a single pivot with a linkage-actuated shock to a unique 5-bar configuration with a variable axle path. So, when the auxiliary shock is set up firm, the initial portion of the axle path is more akin to that of a single pivot, with the swing-arm rotating about the pivot connecting it to the MagicLink. Then, when the auxiliary shock starts to compress and the Magic Link rotates back and down, the axle path becomes more rearward and varies depending on the changing relationship between the two shocks. It sounds complicated, and it is, because the shock rate also alters, depending on set up.

Springs in Series

The name CoilAir finally comes into its own with the MagicLink-equipped bikes as the rear suspension is now both coil and air-sprung.
Because the main air spring on the Fox RP23 shock and the coil spring of the auxiliary shock work in series, the combined spring rate of the system is reduced. This means that you don’t have anything like the same ramp-up that you’d have with the air spring alone. Also, because the CoilAir now has more travel for the same shock stroke (remember that only the main shock provides damping), the compression and rebound-damping are also reduced.

Attitude-adjusted geometry

Using the forward limit-adjuster on the auxiliary shock to line up the MagicLink and the main shock gives the longest effective eye-to-eye length of the main shock. So, when pedal forces pull the link forward into this position, you get the steepest geometry for improved climbing. This also gives the bike a firmer initial suspension setting, as the angle between the main shock and rocker links increases.
Alternatively, you can set the limiter so that the MagicLink never reaches the in-line position, giving permanently slacker geometry and a lower bottom bracket height. Limiting the MagicLink’s forward motion also makes the suspension feel plusher in the initial part of the stroke.

Set-up

While it’s pretty hard to get your head around how Kona’s new MagicLink suspension design actually works, arriving at a baseline set-up is relatively straightforward. You set the sag on the main shock anywhere between 28% and 32% of the shock stroke, then you check the sag on the auxiliary shock, which should be between 1-3mm.
The head-scratching only really starts when you want to fine-tune the set-up. Each bike comes with three auxiliary shock bottom-out elastomers to tune the bike for different rider weights and progressivity. Additionally, two auxiliary shock-mounting positions on the MagicLink also change progression. Adjusting the preload on the auxiliary spring controls how much force is required to activate the MagicLink and seems to change where in the stroke of the main shock the auxiliary shock starts to kick in. So, if you struggle to understand the difference between high and low damping, or what the ProPedal dial on your shock does, the adjustability of the MagicLink-equipped CoilAir will make your head spin.

Mixed Messages

One of our initial concerns was that the elongated, curved swingarm wouldn’t be as stiff as the out-going design. Kona assured us that the new design is actually stiffer, stronger and no heavier, but seeing as the 2.4in Maxxis tyres were almost rolling off the narrow CrossMax ST rims it’s impossible for us to confirm or dispute Kona’s claims. And while we’re on the subject of spec’ing issues, the Marzocchi 55 ATA forks on all of the test bikes managed to have excessive play in the bushings and lots of stiction — not good at all.

The Ride

But enough whinging — the question is: how does it ride?
Firstly, it feels pretty much like a regular CoilAir in terms of cockpit layout and geometry. Next you realise that there is no obvious transition or step in the suspension. Depending on the set-up, both shocks can move in unison or, for a firmer pedalling action and steeper geometry, the auxiliary shock can be adjusted so that it kicks in later in the stroke of the main shock.
However, the effects of the MagicLink don’t go unnoticed — the most obvious benefit being that the 34lb CoilAir Supreme rides and climbs like a considerably lighter bike.
It jumps to attention when you put the power down and there is no noticeable pedal feedback, even when we tried to induce it while revving in the middle or granny rings. Additionally, we couldn’t detect any difference in the level of ‘anti-squat’ between the middle and granny rings. Traction was never a problem, so we can only assume that the suspension was doing what it is supposed to, while climbing.
Under hard braking, the bike feels neutral and doesn’t suddenly sit up or feel weird. This is due to the intentional brake-induced squat of the linkage configuration.
Bunnyhopping the bike, however, seemed to require more effort than normal and this could be due to several factors. Firstly, the CoilAir rides a lot lighter than it actually is, so we may have been underestimating the effort needed to get it airborne. However, a more likely reason for the bike remaining glued to the ground is that the baseline suspension set-up is very linear, so it tends to absorb a lot of rider input, making it more difficult to push against the suspension. This makes it harder to pump through rolling terrain and means there is a tendency to rip through the mid-stroke when bombing through smooth compressions. A couple of turns on the rear adjuster of the auxiliary shock tightened things up, but then it didn’t feel as plush off the top.
Ideally, we’d have moved the auxiliary shock to the secondary (upper) position or fitted the firmer bottom-out elastomer; both of which would offer a more progressive suspension action. With time constraints and a photo shoot it was always going to be impossible to get an optimum set-up on a three-hour ride. Ultimately, the 2008 MagicLink CoilAir has more travel, climbs better and rides lighter than the original, but the jury is still out on whether or not the suspension is more effective given it’s additional complexity.

Moving Forward

So, the next step for us is to get a CoilAir with a working fork and suitable tyres and do some extensive testing with the different suspension settings on home soil. As for Kona’s next step, it is obvious that the MagicLink offers limited benefits for a DH bike, so we expect to see the technology filter down to shorter-travel rigs which need to be ridden uphill as quickly as they descend — possibly a sub-30lb Kona Dawg with somewhere between 140 and 160mm of travel. And if Kona’s new link really is magical, we could even see fork-travel adjusters and platform shocks vanish completely from Kona’s 2009 MagicLink-equipped bikes.